Scientists have been engaged in the study of nuclear fusion hoping to create a clean and infinite energy on earth that is on par with stars. An US science team managed to attain burning plasma in the beginning of this year through high power laser light, and once again had a new discover that point to peculiar and unexplainable ion behaviors.
Scientists at the National Ignition Facility (NIF) of the Lawrence Livermore National Laboratory (LLNL) have been studying nuclear fusion since 2009. In order to generate enormous pressure and temperature, these scientists emitted 1.9 MJ of ultraviolet energy from 192 units of lasers, and reflected the energy onto the hohlraums that are as small as ball bearings, where the internal fuel capsules are then exploded for a chance to fusion atoms into helium that would release considerable energy as a result.
The nuclear fusion at the NIF successfully released 1.35MJ of energy in January this year, which is also the first time when the energy generated from nuclear fusion exceeds total energy input, and marked a new chapter for inertial confinement fusion (ICF) despite merely lasting several nanoseconds.
The research team, upon further analyses, discovered that burning plasma had manifested in an unexpected manner, where the plasma displayed a higher level of energy than model prediction, and the DT plasma that was at thermal equilibrium also had a higher-than-expected average neutron energy. Alastair Moore, first author of the thesis, commented that whatever cannot be predicted by normal radiation hydrodynamics code under ICF simulation is deemed to be unpredictable.
Scientists are treating the unexpectedly high energy behavior of the plasma as a Doppler effect, which refers to how the siren sound from police cars and fire trucks changes when they are near and far away. Moore commented that one of the explanations goes to the disequilibrium between deuterium and tritium ions, which is why a more advanced simulation is required for further studies. More further commented that they are working with teams from the Los Alamos National Laboratory (LANL), Massachusetts Institute of Technology (MIT), and Imperial College London, in the hope of resolving this mystery.
The team believes that the unexpected ion behaviors from the nuclear fusion may offer key interpretations for designs of laser nuclear fusion in the future.
(Cover photo source: LLNL)